2018 BMW M5 vs Mercedes-AMG E63 S Super Sedan Test

Does anyone know if AMG begins with a modified platform, as BMW does, versus the same platform with modifications. BMW M cars are usually only the unibody from the base car, and all the subframe, suspension, drivetrain, sheet metal, etc are basically all new for the M version.

It’s an expensive route but makes a great car that you just can’t duplicate with modifications to a base car (in the BMWs case)